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Arctic beaches show characteristic sedimentary features that readily distinguish them from beaches in more temperate zones. Along the Alaska coastline in the eastern Arctic and subarctic regions of the Bering Sea, many exotic microtopographic structures may persist throughout summer, if spring and summer weather conditions are mild enough. On prograding sections of the coast, similar features might be preserved in the stratigraphic cross section of the beach.
Microrelief features develop in spring and early summer as a result of dynamic processes associated with breakup of sea ice and thawing of kaimoo, permafrost, snow banks, and stranded blocks of ice. On the beach 2 different types of microrelief occur. Along the backshore and the upper foreshore, small streamlets and mud flows fed by melting snow and thawing permafrost produce micro-outwash and microdeltaic deposits. In the swash zone, movement of grounded sea ice by wind and waves produces ice-push ridges; melting of kaimoo ice leaves a kaimoo ridge, and melting of stranded gravel- and sand-rich brash ice creates sea-ice kettles and sea-ice sand and gravel cones. Within the nearshore areas, close to the shoreline, sea ice locally scours the bottom sediment into small randomly oriented ridges and troughs. Farther offshore, small randomly spaced hummocks of coarse sand and gravel form where ice-rafted sediment drops from grounded or stabilized melting sea ice.
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